A 1931 study by Mr. H.W. Heinrich found that for every major injury or fatality experienced, there are 29 minor injury producing accidents and 300 accidents in which no injury resulted.

He was one of the first to point out that concentrating only on accidents that causes serious injury means a vast majority of accidents and near misses are ignored. This being the case, imagine how many unsafe acts are occurring that have not yet lead to an accident or near miss.